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A force pump is a relatively simple device used to draw liquid from a well by hand. Force pumps are considered a type of positive displacement pump because they rely on mechanical force to move water by displacing it from one location to another. An outdoor well pump in a residential yard is an example of a basic force pump.
To operate a force pump, users depress a lever or handle above the ground. Once the handle is depressed, an underground cylindrical piston is forced down into the well. As the piston passes through the water, the water is forced upward around the sides of the piston. Because of the pressure created by this force, the water flows up through an above-ground faucet at a relatively steady rate. A check valve around the piston prevents the water from flowing back down into the well.
This type of pump is often used to draw water for irrigation purposes, and many are also found in agricultural settings. Some older homes may have a small force pump located inside the kitchen to draw water from an outside source. These pumps may be used to draw liquid chemicals or lubricants in industrial or manufacturing settings. Some are found on storage tanks, such as a propane or kerosene tank. The bilge pump on a boat is also an example of a force pump design.
While the standard force pump has a single chamber for drawing water, a double-acting force pump features two separate chambers operated by a single handle and piston. As the piston moves down, water is drawn simultaneously through both chambers. This allows users to draw water more quickly, and produces a smoother and more even flow.
Force pumps are simple to install and operate. They are also relatively affordable compared to more complex pump designs, and require little maintenance. Because these pumps contain few mechanical parts, they are unlikely to break down and can be expected to last for many years.
Despite their many benefits, force pumps may not be the most effective option in certain types of applications. Because of their simple design, these pumps have a very low lift limit. This means they can only draw water from shallow bodies of water. For deep wells, buyers should choose a pump that can fit down inside the well to displace water. Force pumps are also fairly slow and inefficient, and should not be used for high volume applications.
I remember my grandparents had one of these in their yard when I was a kid. They had a small farm, which they used to run as an actual farm, but it eventually stopped being cost effective.
I was fascinated by the pump, and being able to bring up water from underground. But until my grandmother explained, I didn't realize that this was where they used to get all their water. She would go out and fill the saucepans from the pump in the yard when she first moved into that house.
It was kind of a shocking thing to a kid, but I admired her so much for it.
For a while, I tried to go out to the pump every time I wanted a drink, but eventually I started taking the tap for granted again, as do we all, I suppose.
@pastanaga - The problem would be that I'm sure some of those villages have water tables that are extremely low in the summer.
West Africa is near the Sahara desert after all. So, a pump like this isn't always going to be able to reach the water it needs to in order to get it to the people.
For that you need deep well pumps that will go deeper and those can't always be arranged so that you can operate them by hand.
It's an unfortunate situation, because I can see what you mean. But, you know there are always going to be people who understand how an engine works somewhere in the area.
It's just a matter of figuring out what the best option is, actually talking to the people and seeing what they are able to maintain, rather than just giving them an expensive, and ultimately useless present.
This was the kind of water well pump we were always trying to get installed in West Africa, when I was volunteering over there. Often a donor would decide that it wasn't too expensive to install something fancier and would have sometime which involved a motor, or electricity, or was simply more complicated.
Unfortunately, they never thought long term. This kind of pump, like the article says, is simple to use, easy to fix, easy to find parts for (and the parts aren't expensive) and isn't likely to break down for a long time.
It's all very well to give an expensive present, but if it's not going to last more than a couple of years, and if the people don't have the knowledge or money to maintain it, they are less well off than when they started, since they've likely got new gardens by then that need the pump to maintain and no way to do it.
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